You make it sound very exciting, and as if there are many thresholds , when in fact there are only 10.

As to why you are not getting the rewards and what you are doing wrong , probably nothing! except not reading the text where it tells you that you only get the rewards at the end of the competition, and if your kingdom wins the event.

In case I misunderstood  your question.

Did you mean personal events,personal rewards or specifically the task event ?

When passing thresholds, except  personal KvK events, you should get a system message informing you about it.

In any personal (or clan event), including the task event, you should get the level reward straight away.So if you are not then something is wrong. 

Its only in the kingdom events you have to wait till the three days are up,and you have won.

If you are expecting the reward for being 2nd in the league at the moment,again you will have to wait till the event has finished, and still be in one of the winning places.